HLA-DQ genotypes - but not immune markers - differ by ethnicity in patients with childhood onset type 1 diabetes residing in Belgium

Aim The aim of this study was to compare genetic (HLA‐DQ) and immune markers in a large population of type 1 diabetic (T1D) children and adolescents residing in the same environment, but of different ethnic origin: European Caucasians (EC), Moghrabin Caucasians (MC), Black Africans (BA) and of Mixed Origin (MO). Methods Retrospective study, including 452 patients with T1D aged 0.1–17.5 yr at diagnosis recruited at the Diabetology Clinic of the University Children's Hospital Queen Fabiola from May 1995 to March 2013. HLA‐DQ genotyping, diabetes‐associated autoantibodies, organ‐specific autoantibodies, and other markers of autoimmunity were studied. Results The proportion of the different ethnic groups was: 55% EC, 35% MC, 6% BA, and 4% MO. Between these four groups, there were no significant differences concerning age, hemoglobin A1c (HbA1c), presence of diabetic ketoacidosis, random C‐peptide level at diagnosis and 2 yr later. The two most frequent haplotypes were DQA1*0501‐DQB1*0201 and DQA1*0301‐DQB1*0302 with a significant higher prevalence in MC and EC (p = 0.002 and 0.03, respectively). The high‐risk heterozygous genotype DQA1*0301‐DQB1*0302/DQA1*0501‐DQB1*0201 was more frequent in EC than in MC, whereas the homozygous genotype DQA1*0501‐DQB1*0201/DQA1*0501‐DQB1*0201 was more prevalent in MC (p = 0.019). These susceptible genotypes were more frequent in youngest patients (p = 0.003). Diabetes‐associated autoantibodies, organ‐specific autoantibodies, and other immune markers did not statistically differ between ethnic groups. Conclusions These observations in a large population of T1D children and adolescents of different ethnic groups residing in Belgium show significant differences in HLA‐DQ status, but not in diabetes‐associated autoantibodies, organ‐specific autoantibodies, or other immune markers.